T³ Italia Resources

Mood Ring for TI-Nspire CX OS 4.5

Bring science and coding together (no coding experience necessary) while developing a mood ring! The science of color mixing is explored while determining the right body temperature thresholds.

This is an excellent first TI-Innovator STEM and coding project. The project includes variables, loops, conditional statements, Boolean operators and other fundamental concepts in programming.

See the following link for a set of videos with a detailed, step-by-step demonstration of the project for instructors. YouTube playlist video link

Project Overview: The mood ring was invented by Joshua Reynolds. Mood rings enjoyed fad popularity in the 1970s and are still around today. The stone of the ring changes color, supposedly according to the mood of the wearer. The 'stone' of a mood ring is really a hollow glass shell containing thermotropic liquid crystals. Modern mood rings are made from a flat plastic strip containing liquid crystals that is inserted into the hollow glass and mounted within the bezel of the mood ring. The crystals respond to changes in temperature by twisting in a regular way. The twisting changes their molecular geometry, which alters the wavelengths of light that are reflected from the crystals. Wavelengths of light are another way of saying color, so when the temperature of the liquid crystals change, so does the color reflected from the stone. Thus, the ring changes color with the hand temperature of the wearer. In this project, you will investigate temperature measurement using a temperature sensor and then build a digital mood ring that changes the color of the Hub’s Red, Green, and Blue (RGB) light emitting diode (LED) as the temperature your finger changes. You can even display what mood you are in on your calculator!

Background: The Mood Ring project was initially developed to provide a simple and fun introductory coding and STEM activity that appeals to both females and males. The project includes external inputs (temperature sensor), decision logic based on the temperature sensor reading and an output (Red-Green-Blue LED). We have used the project successfully with students and with educators as an introductory TI-Innovator experience. Over time, we realized that the Mood Ring project includes many of the fundamental concepts that are used in feedback and control projects. Recently, we have begun using the Mood Ring project as the initial activity in teacher professional development. The project sets the stage for working through the more advanced Pet Car Alarm and Smart Irrigation projects.